The European law of cross-border cooperation is the legal product of the interplay of different legal orders, namely the international public legal order (Madrid Outline Convention, following Protocols and international agreements enforcing it), the European Union and the national one. To this extent, the European law of CBC is a dynamic process where each of the three components plays a role but none is prevailing from a normative point of view. The paper examines the components of this European law of CBC by looking first at the way CBC is currently conceived by the supranational legal drivers (Council of Europe and EU). It emerges that CBC is not more a matter of dealing with the problems of proximity between communities and territories laying on either side of borders, but of putting together genuine projects for CBC area and implementing a real CBC policy. This implies some consequences. First, CBC as a policy tends to involve territorial units enjoying influential political capacity, such as: federal state, legislative regions or at least inter-municipal association. Even national state may have an interest in participating. The second feature is the institutionalization of CBC as a way to promote coordination of policies, even according to a multilevel governance concept, rather than as an instrument to solve specific cross-border problems. However, this conception of CBC and its consequences must be put into relation with the attitude national states have showed towards CBC. By taking into consideration some factors – namely, the type of decentralization, the intergovernmental relations, the ethnic minorities presence, the influence exerted by supranational actors in countries of democratic transition – we will investigate the potential degree of the national states’ acceptability of the common regulatory solution advanced at the supranational level. To this extent, some specific references will be made to the national enforcement process of the EGTC Regulation in order to enlighten and understand why the EGTC application across Europe is likely to vary.